Wanted: AH QL Motherboard

[adev]

Does anyone have an unmolested AH board that still works? It will have at least one (maybe 2) flying leads, a couple of cut traces, and I believe an inline resistor on one of the wires. My AH board has these, but the wire has become detached at one end and I've no idea where it goes (into one of the chip sockets that I recall). Plus mine doesn't work, one of the non-socketed chips has gone loco...

Cheers!
Ade.

[RWAP]

The AH ROMs were used in various QL motherboards.

What we need to know is

a) What is the issue number on the motherboard (this appears stamped on the motherboard near the CTL sockets at the back. Probably an issue 5 motherboard ?

b) How are the AH ROMs configured - is it two ROM chips, three EPROM chips (one of which is piggy backed on the other ?)

Some photos might help.

When you say it is not working - what are the symptoms?

I have a spare AH ROM set and various motherboards here...

[adev]

Hi Rich,

It was a 2-ROM set, I can't remember the release no, I will dig that out tomorrow, if I can remember where I hid it. IIRC it had a D09 serial number, in case that helps.

Symptoms are random changing patterns on the screen, random fizzes and bleeps from the speaker, random microdrive accesses (both), unaffected by pressing reset (except IIRC when you hold the reset button in, the lightshow stops and waits for you...

I always meant to send it to Tony while he was still offering repairs, but somehow never got a Round Tuit.

Cheers!
Ade.

[RWAP]

Ian Gledhill at Mutant Caterpillar Games does repairs - it sounds most likely to just be a RAM chip which has failed (as you say you have tried swapping the socketed chips for known good ones - the 8301 is a prime candidate!)